This invention relates generally to modular electrical plugs, and more particularly to a modular plug having performance properties which will be in compliance with Category 6 standards.
The present invention also relates to plug-cable assemblies of a multi-conductor cable with a plug at one end terminating the cable and a plug or other electrical connector terminating the other end of the cable, and to plug-cable assemblies which include a load bar operative with the end of a multi-conductor cable coupled with a plug housing.
In view of the continual desire to increase the transmission rate of data through electrical cables, new performance standards are being promulgated for modular electrical connectors. Connectors having characteristics in compliance with this standard will be known as Category 6 connectors, or Cat 6 connectors for short.
Although existing modular connectors such as jacks and plugs, e.g., those having characteristics in compliance with the immediate lower standards (Category 5), might be found to be in compliance with Category 6 standards as well, it is advantageous to develop new modular connectors designed specifically to comply with Cat 6 standards.
Cat 6 modular jacks and plugs are intended to be used in data communication networks to enable the flow of information at higher transmission rates than currently available with known modular connectors, including Cat 3 and Cat 5 connectors. However, data transmitted at high rates in multi-pair data communication cables has an increased susceptibility to crosstalk, which often adversely affects the processing and integrity of the transmitted data. Crosstalk occurs when signal energy xe2x80x9ccrossesxe2x80x9d from one signal pair to another. The point at which the signal crosses or couples from one set of conductors to another may be 1) within the connector or internal circuitry of the transmitting station, referred to as xe2x80x9cnear-endxe2x80x9d crosstalk, 2) within the connector or internal circuitry of the receiving station, referred to as xe2x80x9cfar-end crosstalkxe2x80x9d, or 3) within the interconnecting cable.
Near-end crosstalk (xe2x80x9cNEXTxe2x80x9d) is especially troublesome in the case of telecommunication connectors of the type specified in sub-part F of FCC part 68.500, commonly referred to as modular connectors. The EIA/TIA (Electronic/Telecommunication Industry Association) of ANSI has promulgated electrical specifications for near-end crosstalk isolation in network connectors to ensure that the connectors themselves do not compromise the overall performance of the unshielded twisted pair (UTP) interconnect hardware typically used in LAN systems. It is expected that electrical specifications for Cat 6 plugs will also be promulgated in the near future.
Reference is made to the prior art U.S. Pat. No. 5,628,647 (Rohrbaugh et al., incorporated by reference herein) which describes Cat 5 modular plugs including a management bar or load bar for receiving the conductors in separate conductor-receiving channels. Inter-conductor capacitance in the plugs is reduced by offsetting adjacent conductors, i.e., vertically spacing adjacent conductors from one another, such that the conductor-receiving channels, and thus the conductors, ate arranged in two planar arrays spaced one above the other. The offset conductors help to lower the plug""s internal capacitance.
When certain wire types are used with current modular plug designs, inconsistencies in plug electrical performance have been found when there is a lack of control in the manner in which twisted pairs of wire conductors are loaded into the management or load bar of the plug. The amount of twists and pitch of the twisted pairs are critical elements to the consistency of the electrical performance between plugs of the same design. Wire pairs which become straightened or become intermingled with other wire pairs without a controlled configuration suffer from increased crosstalk. The current process of manually loading the wires into a load bar provides insufficient control over the amount of twists or the organization of the wires making the transition from the multi-conductor cable to the load bar.
The prior art load bar illustrated in FIG. 1 herein, includes first (or rearward), second (or intermediate) and third (or forward) longitudinally adjoining portions, the third portion being situated below the contact-receiving slots and each portion having a different transverse cross sectional form, although the load bar housing is a unitary member. At a top level two channels are formed from a longitudinal indentation or trough on an upper surface of the rearward portion, a shaped cavity or bore in the intermediate portion and a longitudinal indentation or trough on an upper surface of the third portion. A groove is provided in the first and second portions to receive a conductive strip and hold the conductive strip between the channels in the first level and thereby correct an impedance problem arising from the horizontal separation of the conductors received in the channels in this level. At a bottom level two channels are formed from a respective longitudinal indentation on a lower surface of the first portion, a shaped cavity in the second portion and a respective indentation on an upper surface of the third portion. The conductive strips may be strips of metallic material such as copper, strips of conductive plastic, strips of insert molded plastic surrounding a metal strip or an electroplated strip of plastic, i.e., plastic overlaid with metal.
This prior art load bar is a two-level 8-position component, wherein each of the channels for conductors 3 and 6 of pair #3 are defined at a first or upper level by a longitudinal indentation or trough extending on an upper surface of a first portion and extending partially into the second portion, a shaped cavity or bore extending through the remainder of the second portion and an indentation or trough extending through the remainder of the second portion and an indentation or trough extending on the upper surface of the third portion. Similar conductive strip retaining means are provided for retaining a conductive strip between the two channels in the upper level. Each of two additional channels for receiving conductors 4 and 5 of conductor pair #1 are defined at a second or bottom level by a shaped cavity or bore extending through the first and second housing portions and an aligned indentation or trough extending on the upper surface of the third portion. These channels are preferably arranged between the channels in the first level in a transverse direction of the housing. Further, two additional pairs of channels for the conductors of pairs #2 and #4 are situated in the second or bottom level. These channels are also formed by shaped cavities or bores extending through the first and second housing portions and aligned indentations or troughs extending on the upper surface of the third portion.
A terminal blade for the above-described modular plug comprises a flat conductive member having a first portion having an upper edge surface adapted to contact a contact of a mating electrical connector, a second portion adjoining the first portion and having a narrow length than the first portion and a third portion adjoining the second portion and having insulation-piercing tines. A notch is defined in the upper surface to partition the upper surface into two sections, each defining a side of the notch.
It is an object of the present invention to provide new and improved modular plugs and modular plug-cable assemblies including the same.
It is another object of the present invention to provide new and improved modular plugs and modular plug-cable assemblies including such new modular plugs in compliance with Category 6 standards.
It is still another object of the present invention to provide a new device, called a wire aligner herein, for use with a load bar in a modular plug-cable assembly which will control the amount of twist of the wires pairs making the transition from the cable to the load bar.
Another object of the present invention to provide a wire aligner for use with a load bar in a modular plug-cable assembly which will control the organization of the wire pairs making the transition from the cable to the load bar.
Yet another object of the present invention to provide a new wire aligner for use with a load bar in a modular plug-cable assembly which will control the amount of crosstalk in the wires pairs due to straightness or intermingling of the wires.
It is another object of the present invention to provide a new and improved conductor management bar or load bar for coordination with the new wire aligner.
It is a further object of the present invention to provide a new modular plug which combines the new wire aligner, the new load bar and a conventional plug housing.
The present invention includes (a) a new wire aligner, (b) a new wire aligner and multi-conductor subassembly, (c) a new wire aligner and a load bar subassembly, (d) a new wire aligner, load bar and plug housing subassembly which may further include a multi-conductor cable, and (e) a method of assembling a multi-conductor cable and a load bar to achieve substantially the same amount of untwist in each of said twisted wire pairs.
In one preferred embodiment, for example, a wire aligner for assembly with the end portions of four twisted pairs of wires of a multi-conductor comprises: a wire aligner housing having front and rear parts along a central longitudinal axis, said front part defining longitudinally therethrough three channels which are spaced apart horizontally as middle, left and right channels to define a first horizontal plane, and two upper channels spaced apart from each other and defining a second horizontal plane spaced from and above said first horizontal plane. The rear part extends rearwardly from said front part and comprises (a) a pair of left and right separators spaced apart horizontally to define a central space between them and left and right spaces outward of said left and right separators respectively, and (b) a divider extending horizontally between said separators and defining central upper and central lower spaces respectively. These separators are insertable between end portions of said multi-conductor cable such end portions of two twisted pairs may become situated in each of said left and right spaces respectively, and end portions of two other of said four twisted pairs may become situated in each of said central upper and lower spaces respectively. Each of said channels in said first horizontal plane is adapted to hold said end portions of one of said pairs wires substantially straight and parallel to each other as they extend through their respective channels, and each of said channels in said second horizontal plane adapted to hold a single wire of said twisted pair extending through said central upper space.
A wire aligner of this invention may have various configurations and still be applicable for use with cables of one or more twisted pairs of wires, since it provides uniformity and reliability to the untwisting of twisted pairs regardless of the number of twisted pairs that are exposed from a multi-conductor cable and attached to a load bar and thence to a plug housing.
Another embodiment of this invention is exemplified as a method of loading a load bar with the end portions of at least one and preferably four twisted pairs of wires of a multi-conductor cable for subsequent assembly with a modular plug housing. In the case of four twisted pairs, the new method comprises separating said four twisted pairs of wires of said multi-conductor cable from each other, untwisting each of said pairs substantially the same amount while extending the wires of each of said pairs forwardly and positioning said untwisted pairs of wires in said spaced apart channels respectively in said load bar.
In accordance with the present invention, these and other objects are achieved by providing a modular plug including a plug housing made of dielectric material including a plurality of parallel, spaced, longitudinally extending terminal-receiving slots at a forward end and a longitudinal cavity extending from a rear face thereof forward to a location below the slots such that the cavity is in communication with the slots. Each terminal-receiving slot receives a respective terminal blade or insulation displacing contact. The plug also includes a conductor management bar or load bar, arranged in the cavity and defining conductor-receiving channels.